Sound-transmitting apparatus.



A. D. JONES.

SOUND TRANSMITTING APPARATUS.

APPLICATION FILED MAR. 2 I914.

ATTORNEYS WITNESSES A. D. JONES.

souwo TRANSMITTING APPARATUS.

APPLICATION FILED MAR. 2| I914.

1 ,249,409. Patented Dec. 11, 1917.

2 SHEETS-SHEET 2.

a (g. I A I ATTORNEYS UNITED STATES PATENT OFFICE.

ALVA D. JONES, OF PHILADELPHIA, PENNSYLVANIA, ASSIG-NOR OF FORT! ONE- HUNDBEDTHS T0 FRANK LYSTER, OF PHILADELPHIA, PENNSYLVANIA.-

.SOUND-TBANSMITTING APPARATUS.

Specification of Letters Patent.

Patented Dec. 11, 1917.

Application filed. March 2, 1914. Serial No. 821,877.

' reproduced from a record by a sound-box in such; machine toa distant receiver or sound-reproducing device.

It further consists of such apparatus in which the talking machine can emit the sounds at the same time they are distantly transmitted to another reproducing device.

It further consists of an'improved' var able resistance device or mlcrophone for such apparatus.-

It further consists of improved provisions for adapting the transmitting device to the varying tonal characteristics of the sounds reproduced from various records or other sources of sound.

It further consists of apparatus in which individual variable resistance devices or microphones are applied respectively to the individual sources of concerted sounds, such as to the individual instruments of a band or orchestra, each of such devices being adjusted to the tone-quality of its source or instrument, and the circuits from the several devices being connected to mains or trunks connected to a sound-recording device, recording the concerted current vibrations 0r undulations produced by the sound vibrations or undulations upon a blank similar to that in the ordinary sound-recording apparatus.

It further consists of other novel features of construction, all as will be hereinafter fully set forth.

The annexed drawings and the following description set forth in detail one mechanical form embodying the invention, such detailed construction being but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawings- Figure 1 represents a perspective view of a portion of a talking machine equipped with my transmission apparatus, ortions of the apparatus being illustrated 1agrammatically.

Fig. 2 represents a section of the variable resistance device or microphone.

Fig. 3 represents a plan view of a portion of the-'tone-arm and of the sound-box of a talking machine, showing the resistance de vice and its connection to the diaphragm.

Fig. '1 represents a section on the line m-a: in Fig. 3.

I Fig. 5 represents a perspective view of the support of the plurality of resistance devices employed.

Fig. 6 represents a diagrammatic viewof the apparatus for individually conveying the individual sound-created current 'vibraxtions or undulations from the individual sources of sound to be concertedly recorded.

Fig. ;7 representsa perspectivedetail view of one of the variable resistance devices and the 'end'of the lever connected thereto.

Similar numerals of reference indicate corresponding parts in the figures.

Referring to the drawings, the reference numeral 1 indicates the casing'of a talking machine of any'preferred construction, having a rotatable turn-table, 2, and a movably supported tone-arm, 3, carrying a sound-box, 4, and communicating in any usual or 'desired manner with'a horn, 5, or other soundamplifier. The record, 6, ofthe usual disk-' form rests upon the turn-table. A stylusarm, 7, is supported, upon the sound-box and connected at one end to a post or bolt, 8, secured through the center of the diaphragm, 9, of the sound-box, and the outer end of said stylus-arm carries the removable and changeable stylus, 10. All of these parts can be of an desired or suitable construction employe talking machines.

A clamp, 11, is secured upon the tone-arm and has a bracket, 12, in a bearing, 13, of which a stud,14, is rotatable and adjusted by a set-screw, 15, said stud projecting centrally from a spider-frame, 16. A number of variable resistance devices or microphones, 17, which will hereinafter be described in detail, are secured upon the branches of said spider-frame, and each of said devices has one terminal electrically connected by a conductor, 41, to one of a series bf contacts, 18, of a switch device, the movable member, 19, of which can be moved to en age each of said contacts. A lever, 20 is fucrumed upon a bracket, 21, projecting from the clamp upon the tone-arm, and has in the various types of an insulated clamp, 22, upon one bent end, clamping the end of the central post or bolt of the diaphragm of the sound-box, so that said lever will be vibrated in unison with the stylus-arm and diaphragm. The other arm of the lever has a bent end formed with a clamp, 23, which can engage a terminal of one of the resistance devices or microphones which is brought to register with the clamp by rotating and adjusting the spider-frame, and said clamp is insulated from the lever but in electric contact with the terminal of the resistance device and has a conductor, 24, of an electric circuit having a suitable source, 25, connected to it by a screw, 60. The other conductor, 26, of this circuit is electrically connected to the movable contact of the switch. A sound-producer, 27, the detail construction of which forms no part of the present invention is connected in the circuit to produce sound by the vibrations or undulations" of the current in the circuit, and may be located at any distance from the talking machine.

The variable resistance device or microphone 17, four of which are illustrated, consists of a cylindrical jacket or casing, 28, of cloth or similar non-conducting yielding and inelastic material, and the ends of said casing are closed by two cylindrical heads, 29 and 30, of brass or similar electrically conducting material, having each a lug, 31 and 32, respectively, upon the outer side. Bands, 33, are preferably tightly drawn around the ends of the casing to secure it upon said heads. The lug 31 of the head 29 is rigidly secured in thebranch of the spider, and the lug 32 of the head 30 can be engaged by the clamp 23 of the vibrating lever, so that said head can be vibrated from the vibrations of the lever. A disk, 34, of solid carbon and having its inner face smooth and highly polished, is secured in the casing to have the head 30 bear against its outer face. A similar disk, 35, also of solid carbon and having the face opposed to the former disk highly polished, is secured in the casing and at a distance from said other disk to form a space in which is a filling, 36, of granular conducting material, such as carbon, metal or other material, the conductivity of which is varied by rest or disturbance of the granules, such filling or granular body forming a variable resistance or microphone body. A disk, 37, of tungsten or magnetized steel is secured in the casing to bear against the carbon-disk, and a disk, 38, of soft iron is secured in the casing and bears against the rigid head 29, and an annular gasket, 39, is interposed between the edges of said disks and is formed from rubber or similar material to form a yielding and resilient spacer between the disks. A wire, 40, of steel or iron electrically connects the disks. The granular filling or body of the several variable resistance or microphone devices is of difierent consistency, having granules of greater or less size, so that the resistances of said devices will be different and each device adapted to the character of the sounds or tones to be transmitted.

The conductor 41 of each device is connected to the inner carbon-disk, and a shunt- Wire, 42, connects said conductor and the rigid head of the device, to form a shunt-circuit through said head and the magnetic disks 37 and 38.

In practice, the disk having the record to be transmitted is placed upon the turntable, and the spider carrying the resistance devices or microphones is adjusted to bring the appropriate device to have its terminal lug engaged by the clamp of the Vibrating lever. When the stylus is brought into contact with the groove in the record and the turn-table is started, the vibrations of the stylus and diaphragm will be communicated to the lever, which will communicate such vibrations to the movable head of the variable resistance device or microphone connected to the lever. Said vibrations will eXert more or less disturbance in the granular body in the resistance device, thus varying the resistance in the circuit of the producing device and transmitting the sound vibrations or undulations of the diaphragm of the "sound-box by corresponding vibrations or undulations in the electric circuit to the distant sound-producing instrument or receiver.

The circuit in the variable resistance device or microphone passes through the movable head, the outer carbon-disk, the granular body and the inner carbon-disk, and a shunted circuit passes through the magnetic steel disk, the soft iron disk and the head. The variations of the intensity of the circuit will vary the magnetization of the steel and iron disks and the degree of their attraction.

The resistance in each device is different from that in the othersby the employment of larger and smaller granules or of granules of'material differing in conductivity, so that a variable resistance device or microphone of greater or less resistance under varying disturbances may be employed according to the tonal character of the instrument or sound-generator being reproduced.

In Fig. 6 of the drawings is illustrated an apparatus for recording sounds in which my variable resistance device or microphone is employed. Musical instruments and other tone or sound-producing sources have different tonal characteristics which act differently upon diaphragms or other record ing and reproducing devices, and in recording the concerted sounds'from such sources, the sounds from one source are liable, on account of their characteristic influence upon the recorder, to interfere with the sounds 

